you're very lucky today that I also changed that on my site. Use this code for the forumrules template:
HTML Code:
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="280">
<tr>
<td class="thead" colspan="<if condition="!$show['codeonly']">2<else />1</if>">
<a style="float:$stylevar[right]" href="#top" onclick="return toggle_collapse('forumrules')"><img id="collapseimg_forumrules" src="$stylevar[imgdir_button]/collapse_thead$vbcollapse[collapseimg_forumrules].gif" alt="" border="0" /></a>
$vbphrase[posting_rules]
</td>
</tr>
<tr id="collapseobj_forumrules" style="$vbcollapse[collapseobj_forumrules]">
<if condition="!$show['codeonly']">
<td class="alt1" nowrap="nowrap"><div class="smallfont">
<div><phrase 1="$rules[postnew]">$vbphrase[you_may_x_post_new_threads]</phrase></div>
<div><phrase 1="$rules[postreply]">$vbphrase[you_may_x_post_replies]</phrase></div>
<div><phrase 1="$rules[attachment]">$vbphrase[you_may_x_post_attachments]</phrase></div>
<div><phrase 1="$rules[edit]">$vbphrase[you_may_x_edit_your_posts]</phrase></div>
</div></td>
</if>
<td class="alt1" nowrap="nowrap"><div class="smallfont">
<div><phrase 1="misc.php?$session[sessionurl]do=bbcode" 2="$bbcodeon">$vbphrase[vb_code_is_x]</phrase></div>
<div><phrase 1="misc.php?$session[sessionurl]do=showsmilies" 2="$smilieson">$vbphrase[smilies_are_x]</phrase></div>
<div><phrase 1="misc.php?$session[sessionurl]do=bbcode#imgcode" 2="$imgcodeon">$vbphrase[img_code_is_x]</phrase></div>
<div><phrase 1="$htmlcodeon">$vbphrase[html_code_is_x]</phrase></div>
</div></td>
</tr>
</table>